Genius Seymour Cray and the company he founded split up

For nearly two decades, the name Cray Research has been synonymous with supercomputers, those lightning-fast machines used for everything from locating oil deposits to designing nuclear warheads. Not only had Cray seized nearly two-thirds of the world market for number crunchers in the $5 million- to-$25 million range, but it held exclusive license to sell any machine made by Seymour Cray, who is to supercomputers what Alexander Graham Bell was to the telephone.

Now Cray and the company he founded have decided to go their separate ways. In an unexpected move, the firm announced last week that it was splitting into...